Accrescent – increasing in
length or thickness with age (e.g. the calyx after
flowering)

Accumbent – lying against
(i.a. the cotyledons against the radicula)

Accumbent embryo – folded
in a way so that the radicula is directed against the edges of
the two cotyledons; the cotyledons in an embryo developed from a
curved ovule (accumbent embryo) are in the plane formed by the
longitudinal axis of the seed and the chalaza

Actinocytic stomata –
radiate-celled stomata; two guard cells surrounded by a circle of
radiating subsidiary cells; with five or more somewhat radially
enlarged or elongated subsidiary cells surrounding the guard
cells

Actinodromous venation –
three or more primary veins diverge radially from a point at or
above the lamina base and proceed towards the margin

Aliform axial parenchyma –
a paratracheal axial parenchyma in which lateral wings are
present as seen in cross-section; parenchyma cells surrounding or
at one side of the vessel and with lateral extensions

Allelocytic stomata – with
an alternating complex of three or more C-shaped subsidiary cells
of graded sizes surrounding the guard cells

Altingioid leaf tooth –
basically asymmetrical, with a persistent transparent gland at
the apex, and with their lateral veinlets free, not reaching the
medial vein

Alveolate – with pits
resembling a honeycomb

Alveoli – surface cavities
or depressions, like a honeycomb

Amentiferous – bearing
catkins

Amentiform – resembling a
catkin

Ament(um) – a slender,
often pendulous, cylindrical inflorescence with crowded
(sub)sessile unisexual apetalous flowers, falling as a whole
after fruiting

Amoeboid tapetum – see
Amoeboid-periplasmodial tapetum

Amoeboid-periplasmodial
tapetum – the young microsporocytes are in the centre of the
anther locule and surrounded by tapetal cells; as the
microsporocytes separate, the cell walls of the tapetal cells
degenerate and develop plasmodesmata which connect the
protoplasts of the tapetal cells; the protoplasts fuse and form a
multinucleate periplasmodium surrounding the
microsporocytes/pollen tetrads; the periplasmodium is enclosed by
a perispore membrane

Amphianisocytic stomata –
the two guard cells are covered by four subsidiary cells in two
layers at right angles (not parallel) to the guard
cells

Amphibious – plants
adapted to life both on land and in water

Amphicarpous –
(Schoenoplectus in Cyperaceae) applied to a small
secondary inflorescence occurring at the base of the
culm

Amphisarca – indehiscent
multilocular many-seeded fruit, with a dry and hard outer part
and a pulpy and soft inner part (i.a. a melon)

Amphitropous ovule – with
the ovule apex and the stalk base next to each other and with the
megagametophyte curved; attached near its middle, half-inverted,
with the raphe terminating approximately half-way between the
chalaza and the orifice

Anatropous ovule –
reversed; inverted at 180o parallel to its stalk so
the micropyle is close to the point of funiculus
attachment

Anaulcerate pollen grain –
with ulcus/ulci distal on the pollen grain

Androclinium – see
Clinandrium

Androdioecious – with some
plants bearing only functionally hermaphrodite flowers and other
plants functionally male flowers

Androecium – a collective
term for the stamens in a flower

Androgynophore – a stalk
carrying both stamens and carpels/ovary above the insertion of
the petals

Andromonoecious – a plant
with both male and hermaphrodite flowers, but without female
flowers

Androphore – a stalk on
which the stamens are carried

Andropodium – a structure
consisting of connate staminal bases

Anisocytic stomata –
unequal-celled stomata; the two guard cells are covered by three
subsidiary cells, of which one is markedly smaller than the other
two; with three subsidiary cells, two large and one smaller,
surrounding the guard cells

Anisophyllous – where the
two opposite leaves at a node are of very unequal size or
shape

Anisomorphic leaves –
leaves of usually two different morphological types on the same
shoot or at least on the same plant

Annual shoot – shoot
sprouting from the perennial root/stem system and lasting only
one growing season

Annular – in the shape of
a ring; used of any organs arranged in a circle

Annulus (pl. annuli; of
pollen grains) – area of exine surrounding a pore and sharply
differentiated from the remainder of the exine

Anomalous – out of the
ordinary, unlike others in its group

Anomalous secondary growth
– secondary (lateral) growth that does not follow the normal
pattern of a single vascular cambium producing xylem to the
inside and phloem to the outside

Anomocytic stomata – the
stoma is surrounded by a varying number of subsidiary cells
resembling normal epidermal cells (the subsidiary cells with the
same appearance as the guard cells); stomata lacking
differentiated subsidiary cells surrounding the guard
cells

Appendicular epigyny – the
initially convex ovary becoming inferior by early vertical growth
beneath the tepals making the entire apical meristem concave;
initiation of the youngest floral primordia occurs on this
concave meristem; the inferior ovary forms through congenital
adnation of the carpels to the bases of the tepals and stamens; a
central concavity develops in the convex top of the floral axis
due to development of appendicular tissues

Appendiculate – with
appendage or appendages

Appressed – lying close
and flat (e.g. hairs on a stem)

Aquatic – living in
water

Arachnoid (type of
indument) – cobweblike, tangled cottony, the hairs in several
directions and tangling

Arborescent – becoming
tree-like

Arbuscular endomycorrhiza
– vesicular mycorrhiza; a type of mycorrhiza with glomeromycetes,
in which the fungus penetrates the cortical cells of the roots;
the mycorrhiza forms highly branched characteristic structures,
arbuscules or vesicles, exchanging water and nutrients; in the
Arum type hyphae grow in the intercellular space, whereas
in the Paris type hyphae grow between the cells

Arbutoid mycorrhiza –
penetrating the outer cortical cells of the hair roots, although
these are covered by a Hartig net, in which the hyphae grow along
the cell walls or form an entire envelope

Archespore – one or
several cells from which the megasporocyte or microsporocyte
develops; the archespore may be unicellular or
multicellular

Arcuate – curved like a
bow

Areolate – with an areole
or areolae, divided into distinct spaces by boundary
lines

Areole (areola, pl.
areolae) – areas on a surface divided from similar areas by a
division line such as a vein; in Cactaceae: a modified
axillary short shoot

Ascidiate carpel – tubular
to pitcher-shaped, widening in upper part; the carpel primordium
is initially U-shaped, and if the area between the arms of the U
becomes meristematic (the meristematic cross-zone), the carpel
develops as if it were a tube – Opposite: plicate
carpel

Asepalous – without
sepals

Asperous –
rough

Asperulate – slightly
rough with small hairs

Asperulous – slightly
rough

Asterad embryogenesis – a
three-tiered proembryo is formed with a vertical division in the
apical cell and a transverse division in the basal cell; the
apical cell may divide by an oblique wall and, at the time of
formation of a quadrant, a wedge-shaped epiphysis initial is cut
off which later gives rise to the epicotylary region; the
remaining three cells of the quadrant produce the cotyledons; the
middle cell of the proembryonic tetrad gives rise to the entire
hypocotyledonary region

Asterosclereid,
astrosclereid – a fairly short sclerenchyma cell (sclereid) that
differs from a brachysclereid by its often conspicuously branched
shape

Astringent taste – making
the mouth pucker, bitter

Asymmetrical – with the
two sides of the part or organ not equal – Opposite:
symmetrical

Atactostele – a type of
stele in which the vascular bundles are arranged irregularly
within the parenchyma (ground tissue)

Autogamous –
self-fertilizing, when ovules are fertilized by pollen grains
from the same flower

Awl-shaped – gradually
tapering to a sharp thin point

Awn – (Poales) a
fine bristle ending an organ

Axial parenchyma – type of
secondary xylem parenchyma, in which the parenchyma cells
originate from fusiform cambial initials; the cells of the axial
parenchyma may be as long as the fusiform initials from which
they originated or, usually, much shorter due to transverse
division prior to the differentiation

Axicorn –
(Campanuloideae) tissue on the inside of the fruit, which
by its drying perforates the pericarp and allows the seed being
dispersed

Axil – the angle between
the stem and the leaf

Axile – belonging to the
axis

Axile placentation – the
ovules are attached to the axis of the ovary, to the inner angle
of the cells of a syncarpous ovary, in which the placentas are
situated in separate locules; the ovules are attached along the
sutures of the closed carpel, i.e. in the corner formed by the
ventral areal of the carpel in an apocarpous or syncarpous
gynoecium

Axillary – arising in an
axil, the point between the stem and the leaf or another organ
which arises from the stem

Axillocytic stomata –
stoma in an axillary position attached to two lateral walls at
the distal, marginopolar end of the single subsidiary
cell

Axis – main line of
development of a plant or organ; (of inflorescence) the main stem
or branch part from which the flowers are produced; (of ovary)
the central column or the central part where the inner angles of
the cells meet